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The Moon's Remnant Magnetism

Although the Moon does not appear to have a magnetosphere surrounding it, it *is* a magnetic object in space. Scientists think that the magnetism of the Moon's surface is leftover from a time when the Moon's magnetic field was actively created by a dynamo within the lunar core, and that this remnant magnetism may gradually erode away.

Theories also suggest that the Moon's magnetism may come from collisions with other celestial bodies such as asteroids and comets, which might have
imparted to the Moon some magnetic properties.

Some regions of the Moon's surface are more magnetic than others. A
strip of the lunar crust called the Rima Sirsalis seems to be very strongly magnetic. Measurements of the uneveness of the magnetism and depth of the lunar crust such as those being made by the Lunar Prospector mission can supply information
about the magnetism of the surface, as well as the size and electrical conductivity of the
lunar core. Ultimately these measurements will help scientists
better understand the Moon's origins. For example,
if the core contains more magnetic elements (such as
iron) than the Earth, then the collision/ejection theory of lunar origin loses
some support.

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